The present invention relates to a technology for communicating data among a plural number of information processing apparatuses through a communication network.
Through a home network located within a house being built up with using communication means therein, such as, a wired LAN or a wireless LAN or the like, it is possible to view digital contents of pictures, which are stored in a STB (Set Top Box) and/or a device, such as, on other STB or other PC. Also, other than the method of passing through such a network, through a bridge medium, such as, a SD (Secure Digital) card or the like, it is possible to view the digital contents on a PDA (Personal Digital Assistants) and a portable telephone (a mobile phone).
Various decoders are provided, being different in the kind thereof, depending on the resolution of a screen, the processing power, and/or the size of a memory, etc., which are provided in the device; i.e., many kinds of methods for compression and coding is installed into a PC having high resolution and high processing power, while into the mobile phone having a display screen of QVGA (Quarter Video Graphics Array) is installed a compression/coding method of high compression, for reducing the data size of digital contents, such as MPEG-4 (Moving Picture Expert Group-4), etc., to be small.
In this manner, since the reproducible moving pictures differs in the format thereof, depending on the kinds of terminals, there is necessity of converting the contents thereof for achieving common use of the contents between the terminals. Such the conversion on the formant of moving pictures is called by “trans-coding”.
Generally, the trans-coding is executed within one (1) set of a processing apparatus, in many cases, which installs software or hardware having capacity of the trans-coding. However, since the contents themselves are large in the data size, and further large in the throughput thereof, it takes a very long time until when the process is completed, in particular, for the processing apparatus installing therein no hardware for the exclusive use thereof, but depending on the processing speed of a CPU and/or the size of a memory.
Then, studies were made upon a technology of executing the trans-coding within a short time-period, through executing the trans-coding in parallel upon the contents divided by a certain unit for processing, with using a plural number of processing apparatuses therein. In this, the contents of MPEG are divided into a unit of data block, being called by “sequence”, and the data blocks are transferred to the plural number of processing apparatuses, thereby executing the trans-coding thereon in parallel (for example, Patent Document 1).
Also, there is already know a technology of installing a distribution function and a trans-coding function in each of the apparatuses on the network, for the purpose of conducting the trans-coding on a plural number of streams, thereby distributing the data streams to the most suitable processing apparatus, by taking into the consideration thereof the processing performance and the format to be converted (for example, Patent Document 2).
[Patent Document 1] Japanese Patent Laying-Open No. 2004-159079 (page 7 and FIG. 4); and
[Patent Document 2] Japanese Patent Laying-Open No. 2002-374317 (page 9 and FIG. 14).